A derivative security that gives the holder the right to purchase securities (usually equity) from the issuer at a specific price within a certain time frame. The main difference between warrants and call options is that warrants are issued and guaranteed by the company, whereas options are exchange instruments and are not issued by the company. Also, the lifetime of a warrant is often measured in years, while the lifetime of a typical option is measured in months.

A warrant is like an option. It gives the holder the right but not the obligation to buy an underlying security at a certain price, quantity and future time. It is unlike an option in that a warrant is issued by a company, whereas an option is an instrument of the stock exchange. The security represented in the warrant (usually share equity) is delivered by the issuing company instead of by an investor holding the shares.

Warrant certificates have stated particulars regarding the investment tool they represent. All warrants have a specified expiry date, the last day the rights of a warrant can be executed. Warrants are classified by their exercise style: an American warrant, for instance, can be exercised anytime before or on the stated expiry date, and a Asian warrant, on the other hand, can be carried out only on the day of expiration.